Apparatus for machining serrations in metallic bodies



1943 R. I l. TouBHANs 2,327,944

APPARATUS FOR MACHINING SERRATIONS IN METALLIC BODIES Filed Dec. 19, 1941 2 Sheets-Sheet 1 [N VENTOR F8276 h. 7Zz a)75.

A TTORNE Y5,

Y AugQ24, 1943. R. H; TOUBHANS 2,327,944

APPARATUS FOR MACHINING SERRATIONS IN METALLIC BODIES Filed Dec. 19, 1941. 2 Sheets-Sheet 2 MENTOR Fave H TTORNE Ks.

Patented Aug. 24, 1943 non MACHINING 'SERRATIONSI Y m mn remrono ms Rene H. Toubhans, Dearborn, 'Mich assignor to (lenturylviotors Corporation, Drearborn, Mich., azcorporationof Michigan.

Application December 19, 1941,. Serial No. 423,641

A 13.0mm. (01.29 105) This invention relates to mechanism. for .ma-

chining serrations, in metallic. bodies and. hasfor its principal object the'provisioh. of .a cutter head for this purpose involving a, novel typeof cutting tool providing an, exceptionally longlife thereto.

Objects of the inventioninclude the provision of a cutter head for use inmachining'curved-serrations in metallic v bodies including a. head and a plurality of cutter blades disposed at generally radial relation with respect thereto, thefcutter shown in'Fig. 1 after its end face has been" serratedby the cutter head of the present inventionya'nd, j 1 7.

Fig. 1151s .an'enlar-ged, transverse'sectional view -taliendiametrically through the piece of workas on the line l-l'--H t Fig. 10.

The present inventionis appnca l'e for use in t the serrating of a, surface. of apart which is blades-each comprising a cylindricalelementhaving a grooved or ribbed periphery and. cut away over its length for a. portion of its periphery to present. a serrated cutting edge; the provision of a. cutting tool of the type described inv which the cutting elements or blades are provided with thread-like grooves intheir periphery; the provision. of a cutting tool of the type described including novel means for locating the cutter elements or blades radially of the supporting head therefor; the provision. of; a cutter head of. the

type described including novel means iorsecuring. the cutting elements for blades in position in the head; and the provision of atoolof the type described that is sturdyin construction. and

long lived.

The above being among the objects of the present invention. the same consists in-certain novel featuresof construction and combinations; of parts tobe hereinafter described with reference to-the accompanying drawings, and then-claimed, having the above and other objects in view.

In the accompanying drawings which illustrate a. suitable embodiment of the. present-invention andin which like numerals refertdlikeparts: throughout the several different views, i

Fig. 1 is a fragmentary, side elevationalyiew showing the cutter head constructed in accord"- ance with the present invention mounted" upon the spindle of a lathe in operative relationship with respect to a pieceofwor-k; I t r Fig. 2 is an enlarged view of. the operatingiface ofthe cutter head shown inFig. 1;.

Figs. 3 to 8, inclusive, are enlarged fragmene tary sectional views taken on the;;lines 3,- 3 4- 2; 5-5; 6B; l'.l', and: tie-8;, respectively,

of'.Fig-.2; i h a Fig, 9-is a reduced fragmentary VlQWiOf the operative face ofthe' cutter head shown in; the preceding views illustrating the manner in which the cutter blades arelocked'in radially adjusted position and with the, cutter'blades .radiallyshifted from the position shown in the preceding. fig

ures; v. r

Fig, 10 is an end. View. of the piece of work adaptedto be arrangedlinabutting relationlwith respect to the complementarily serrated surface of, another part. adapted .to be connected thereto. The interfittingcurved serrations of .the two faces in such. case serve as a means, for preventing relative displacement between the two parts in the plane. of their mating faces except'in the directionott he-length of the serrationsthemselves. Broadly speaking, such serrated connections. may be employed. between-any two members, having abutting faces. regardless ofthe character or construction. of the members. However, one such use is in the connection between the various separately formed partsof a biiilt-up ci'ankshaft such as shown and claimedv in; United" States Letters Patent. No. 2,013,039, issued'Sept. 3, 1935v to Julius Dusevoirh Wheresuch serrated connections are to be employed between the various elements of a built-up machine. part, such as the crankshaft disclosed. in said Unitedstates' Letters Patent above identified, it is essential in obtaining, the desired finalresult that the. serrationsb nj opposed faces. o'fsuch elementbe accurately formed, and where one or more. of the elements are 'to 'be interchangeable with other similarly formed elements it willbe appreciated that a uniformityof size, contour and. location. of such serrations is necessary in order to obtain the desired result. The presentinvention provides a 'meansby which such uniformity of result may beobtaine l'in the desired-state of accuracy and finish.

In' the drawings, by way of illustration only, and asindicated in Figs. 1,. 10 and 11, the piece of. workthere shown comprises a shaft-sections:

or other cylindrical, piece of work zll'liavinghn end. face arranged in perpendicular relationship with-respect to itsv axis. As best brought outfin Figs. 10 and 11 which show-such piece of work 29 with itsend surfaceinifinished serratedcondition, such end faceis provided. with a multiplicity of parallel serrationsjfil" thereon, such serrations being of; curved oonformationstruck.from a common center'outside of the periphery. ofthe piece ofi'work and, ofcourse, of uniform siz'e' throughout. While in the broader aspects of. the

invention the particular cross-sectional contour.

ofthe serrations 2 may vary considerably as 'of the spindle 30.

y tion with respect thereto.

, drawings.

long as such contour is such as to permit the serrations on a pair of members to be connected thereby to be readily interfitted by engagement of and disconnected from each other through separation thereof, the serrated faces, for the purpose of illustration the serrations 24, as best brought out in Fig.'1l, are of triangular section having straight sides all disposed at equal angles with respect to the general plane of the surface on which they are formed.

The cutter head of the present invention may be employed with any suitable machine tool that is provided with a rotatable spindle and asupport, that may be moved relative to each other in the general direction of the axis of the spindle. An ordinary lathe is illustrative of this type of machine tool, is satisfactory for use with the cutter head of the present invention, and is illustrated in part in Fig. 1. In that figure the bed ofthe lathe is indicated at 25, the head stock at 28 and the spindle at 35. The usual carriage 32 is illustrated as of a conventional type mov able in a direction parallel with the axis of the spindle 38 upon the ways 34. The usual crossslide on the carriage 32 is replaced by a cross slide 35v of greater dimensions axially of the spindle 35 than the conventional slide and on its upper surface is supported a pair of spaced V- blocks 38 and 4B and which serve to support the work 25 with its axis in parallelism with the axis Suitable clamping mechanism indicated generally at fiil'is associated with the V-block 38 for securing the work 20 rigidly in place during the machining operation and, if desired, similar clamping mechanism may be. employed in connection with the V-block '55.

The cutter head of the present invention is mounted upon the spindle 35 in a conventional manner for operation upon the lefthand end face of the work 25 as viewed in Fig. 1. This cutter head comprises a cylindrical supporting or cutter head 50 having a concentric hub 52 concentrically mounted upon the outer end of'the'spindle 3E) in accordancewith conventional practice. may be conveniently formed of a casting or forging. The head 50 supports one or more, and

preferably a'plurality as shown, radially, disposed cutting elements or blades, indicated generally at 54, which are exposed on its operative end face, the righthand face as viewed in Fig. 1, for engagement with the work. 25. The cutterb-lades or elements 55 as. brought out in the various views are each ofgenerally cylindrical character having reduced concentric cylindrical inner ends 55 and outer ends 55. In accordance with thepresent invention the cylindrical main body portion of each cutter element or blade 54 is provided on its surface with a plurality of equally spaced grooves forming between them ribs 58 extending in a generally circumferential direc- In the broader aspects of the invention the ribs 50 may comprise a plu rality of separate ribs each arranged in a plane perpendicular to the axis of the associated cutterelement or blade 54, or they may comprise a continuous thread-like rib. This latter form is preferable for the reason that it is more easily andaccurately formed than the first type and, accordingly, this form of rib is illustrated in the The ribs 50 are of a cross-sectional configuration complementary to the cross-sectional configuration of the serrations 24 desired in the work and, accordin gly, withthe cross-sectional configuration of the serrations zilassumed cutter element or blade 54, the main body por- 7 tion on each cutter element or blade 54 is provided-in its outer surface with an axially parallel groove or recess 62 each side wall of which preferably lies in a plane including the axis of the corresponding cutter element or' blade 5-1.

blade is so disposed as to intersect the ribbed periphery of the main body portion along an approximate line parallel to the axis of the cutter element or blade so as to form the cutting edge 64. The cutting edge 64 is, therefore, of

serrated or irregular conformation in face View complementary to the cross-sectional configuration of the serrations 24 desired to be formed on the work. In order to receive the cutter elements or blades 54, the head is provided in' its opera,-

tive end with a like member preferably equally angularly' spaced partially cylindrical recesses for reception thereof. The recesses are of'such depth as to expose a'portion of each cutter ele-F ment or blade 54 axially outwardly beyond the I operative end face of the head 50 and each cutter blade or element 54 is so positioned in its co'rresponding recess that its cutting edge 54 thereof is exposed axially outwardly beyondsuch operative end face of the head 55. Theserecesses are, furthermore, arranged with their axes radial with respect to the axis of rotation'of the head 50 so that the cutting edges 64 of the-blades may be disposed in radial relation with respect to the axis of rotation of the head 50. Each recess comprises a central partially cylindrical portion 10, best brought out in Figs 4, 5.and 6 of a radius substantially equal to the radius of the main body portion of the corresponding cutter'element so that the latter is relatively closely received therein, and partially cylindrical 45 concentric end portions for relatively closely 'receiving the end portions 56 and 58 of the cutter blades or elements 54 as particularly brought out in Figs, 7 and 3, respectively. The length of the portion 10 of each recess is preferably slightly greater than the length of the main body portion of the cutter blade or element'54 received therein for a purpose which will hereinafter be brought out.

The forward wall, in the normal direction of rotation of the head 50, of each recess is cut away as indicated at H in Figs. 5 and 6 to provide an opening on the operative end face of the head 50 leading into each recess of suflicient width to pass I centrally cut away for complementary reception of a plate member 12. The plate member 12 is.

formed to provide a central cylindrical boss portion 12a and an overhanging flange portion 12b extending radially outwardly therebeyond.

Screws l6 projected through the plate member 12 1 and threaded into the head 5llserve to secure the plate member 12 in place. The overhanging flange portion 12b of the plate member 12 is provided with a notch 96 in itsperiphery at the inner end of each cutter blade or element 54, and that side of each of said notches more advanced agendas in the direction of normal turning movement of the cutter head is radially disposed with respect to the axis of rotation of the cutter head and is aligned axially of the cutter head-with theaxis ofthe cooperating cutter blade 54. The notches so extendradi-all-y inwardly of the member 12 to the cylindrical portion 12!; thereof andthe cutter blades 8 stop short of such portion Ma so that only the unnotohed portion of the flange portion 12b overlaps the inner ends of the cutter blades 54* and then only over those portions thereof in which the grooves 6-2 are located. r v

In centrallyflcuttingaway the operative end face of the head 5!! for reception of the plate member 1-2, it is cut away to suoh a depth that the axially i-n-nerflface of the flange portion: 12b

lies in the planeof the axes of the cutter blades or elementsilfl, as best brought out in Figs.'6 and B and in which position the axially outer face of the plate member may project slightly outwardly beyond the operative end face of the head 50. As best brought out in Fig. 6, those portions of the flange lib which overlap the inner ends of the cutter blades or elements54' are cutaway for complementary reception in the inner ends of the grooves ill and the bottoms of the grooves 62 in the cutter blades or elements 54, and the plate member l2 thus serves as a clamp to maintain the inner ends of the cutter blades or elements in the bottom of their corresponding grooves 10. It will be observed from an inspection of Fig. 6 that the I radial wall of each notch 96 abuts against the outermost and radially disposed wall of the groove62 in-the corresponding cutter blade or element 54 and thus serves as a'sto-p in engagement with such-wallof the groove 62 positively preventing further rotationof the cutter blade or element 54 in a counterclockwise direction of rotation about its own axis; as viewed in Fig. 6'. This feature serves as a means for locating the cutting edge of each cutter blade or element 54 in radial relation with respect to the axis of rotation of the head 55 as will hereinafter be more apparent.

, As indicated best in Figs; 2 and 3 the operative end face of the cutter head is also axially cut away as at 'EBacljacent'the outer end of each cutter bladereceiving recess to a depth-equal to the radius of the outer ends 58 of each cutter blade or element, and aclamping member 80 is received in each recess it with its outersurface in substantially flush relationshipwith respect to the operative end face of the head 50' and with one end thereof shaped to correspond to and arrangedin complementary engagement with the v outer surface of the corresponding reduced end portion 58. The clamping members ildare each drawn into positionby means of a screw 82 projected therethrough and threadedinto the head 50 as indicated best in Fig. 3.

It will be appreciated that when the cutter head is rotating during a cutting operation ,thecutting edge 64 in engaging and removingmetal from. a piece of work will be subjected to a iorce tending to turn the cutter blade in a clockwise direction of rotation as viewed in Figs. 4, 5 and 6, and that the clamping action of the plate 12' on the inner ends of the various cutter blades and the clamps 8!] on the outer ends 58 of the various cutter blades would probably be insuffici'ent to maintain the rotatable positions of the cutter blades about their ownaxesparticularly during a heavy cuttingoperatioii To-overcomethepossibility of such movement of the cutter: blades or elements thunder such conditions an elongated strip of metal: or key to; best shown in Figs. 4.; 5

and 6', is positioned; in that side of the grooves 62-. of: each cutter bladelopposite the cutting edge 61% thereof. Each. key. 99;. is preferably shaped to fit. the bottom of the corresponding recess 62, and the. associated end wall. thereof and is; of a. thickness. equal to the depthof the associated groove 62; so. as to enable it to; be moved, it necessary, with-its blade 54. into. the cylindrical portion ,of the corresponding recess it. The keys extend over the length of the portion 01: each blade receivingtrecessand are of such dimensions. circumferentially of the blades thatthe-ir outer edges; are positioned; inwardly of the plane of the outer: operative end face of the cutter head 50-.

xA. n1urality-or creW 9 a e. thr e to h end face or the head 50' in axially parallel relation with respect. thereto in such position that the: heada thereof overlap the outer edges of the keys at}, as indicated in Figs. Z and-e, so as to act through. the. keys .90 to lock the corresponding cutter blades or; elements 54 against rotation in a clochwise direction in their corresponding recesses as viewedin Figs. 4, 5 and 6'. The outer end face of the head 50- is; preferably recessed; as; at 9.4 for reception of the heads of the screws 92 so, as to enable suchheads to be arrangedin. at, least flush relation with respect to the operativevend face of the head 50. It will, of course, be appreciated that by threading the various. screws 92 inwardly from the position indicated in Fig. 4 that they; may act through their corresponding keys 90 to tend; to rotatethe corresponding cutter blades 54 in a counterclockwise direction of rotation as viewed in Elsi By means of the keys 9.0 and: screws 92;- the various cutter blades; or elements 54 are, therefore, firmly anchored against rotation in the head 50. under the force of a. cutting operation, v In; drawing down the various screws 92 the cutterblades 54 are rotateduntil the clockwise wall of the grooves 62.- thereof, as viewed in Figs. L5. and 6, engage the radially extending edge of the corresponding notches 9.6 which thus automatically locates the cutting geclges of the blades in their desired radial relation with respect to the axiscf rotation, of the cutter head In employing the cutter head thus described 'in forming. the serrations 24 on the end of the piece of worl; 20 it will be appreciated. that the cutter head caused to rotate and the: carriage32 is operated to movethe left-hand end of the work 20; as viewedin Fig. 1 to the left; as viewed in- Fig.- 1' so that such. end is brought into a position to be successively engaged by the cutting edges 64oi thei various blades 54 to'remove metal; therefrom in complementary relationship with respect to. the serrations desired. As will be appreciated from an inspection of Fig. 10 which, indicates that the serrations 24 are all struck from a. center outside of the periphery of the worklt, the work 2!! will necessarily be positioned with its axis eccentric to the axis of rotation of the head 50. during, this machining operation;

Itwill also beappreciated that the high;points of the serrated cutting-edge 64'; of each blade 54 will have to be in circumferential alignment about the axis; of'rota-tionpofthe head 5|]; with the corresponding highpoints of 7 the serrated cutting edgesof the remaining b1ades. -6,4=.. In order to insure such circumferential alignment oi the high points of the cutting edges-S4; of; the various blades 54 the follow n s ibedlme ha nism is. emp oyed Asxindicatedbest in Figs.)

an'd8 the operative: axialend face ofthe head 50 is provided with a circular. and concentric groove. E69 therein. Substantially. filling the groove Mil between each adjacent pair of cutter blades 55 area pair of segmental locating members Hi2 and HM 'slidable relativeto each other inthe groove IE9. he'segments I02 and I04 are provided with slots I05 therein, elongated in the direction of length of the segments, and through which bolts .or screws Hi8 are projected and threaded into the head 50 for the'purpose of clamping the segments in circumferentially'adjusted position. 7 g

As best brought out in Figs. 2 and 5 the corresponding ends of each pair of segments I02 and IM are serrated for complementary engagement with the ribbed or threaded surface of the associated cutter blade 54, but as particularly brought out in Figs. 2 and '9 the serrations on the end of the segments [02 are so radially offsetfro'm the serrations onthe ends of the segments HM that when the high points of the serrations of one segment are interfitted in the bottoms of the grooves or received midway between the ribs 60 of the cooperating cutter blade 54, the high pointsof the serrations of the other segment are centrally aligned with suchribs 6E). Consequently when the high points of theserrations of a segment I94 are received in the bottoms of the'grooves iormed'between the ribs on a cutter blade 5 the high points of the serration of the associated segment I02 are in opposed relation withrespect to the tops of the ribs 60 of the associated cutter blades. The serrated ends of all of thesegments I52 are arranged with the high points of the serrations at corresponding distances from the axis of rotation of the head E! and the high points of the serrations on all of the segments I04 are likewise arranged with such high points at corresponding distances from; the axis of rotation of the head 5i Consequently when the cutter head is set upfor a cutting operation, in order to insure that the high points of the serrations of the various cutting edges Bi! of the cutter blades 64 are arrangedat corresponding radial distances from the axis of rotation of the cutter head,

before thevarious cutter blades'54 are clamped in position, either one set or the other of the segments I02 and'lfld, shown in Fig. 2 as the segments Hi l, are slid circumferentially in the groove Hill until the serrated ends thereof are in accurately intermeshed relation with respect to the ribbed exterior of the associated cutter blades 5d, the'cutter blades 54 being adjusted axially thereof in their associated recesses in the head 59 if necessary to bring about this relation; and then the screws N18 are tightened down. This operation acts to positively look all of the cutter blades 54 with their serrated cutting edges in a corresponding position radially of the axis of rotation of the cutter blades. The cutter blades are then clamped in position and the cutting operation is performed with the assurance that the high points of the serrations of the cutting edges Gil of all the cutter blades 54 will be circumierehtially aligned with each other and theserrations 2d formed on the work will be of true and accurate conformation.

"it will be appreciated that if two cylindrical pieces of work, such as the workpiece 20 illustrated, or equivalent pieces of work, are supported in the same position in the lathe shown and are serrated with thesame positioning of the cutter blades 54. when the two pieces of work are. positioned with their. serrated faces in con tacttheserrationsof both pieces cannot'be a1;- ranged' in. interfitting relation; with respect .to each other, This is because the highpoints-of the serrations .on cheer the pieces must 'fit;with-.

in the low points of the; serrations of the other. e of the pieces in order to effect a perfect inter fite ting relationship, requiringthe high points of the'serrations of one pieceto'correspond in our: vature to the low points of the serrations of the other piece, whereas, under the conditions-assumed, the high points of the serrations-on-both pieces are struck from equivalent centers. Accordingly, in order to have the serrations of one of the pieces accurately interfit with the serrations of the other of thenpiece's, when such pieces are arranged in end-to-end relationship,

it is necessary that the serrations of one piece be-offsetjfrom, the serrations of the other piece about a common center for allof the serrations of the screws I98, the segments I04 are backed out 'of engagement with their corresponding cutter blades: 5 and thejsegments N32 are moved into engagement with such cutter blades" which-are then shifted radially their corresponding recesses so that the serrated endsqof the segments I92 are now arranged in interfite ting relationshipwith respect-to the ribs exterior-of the cutter blades 54' as indicated in Fig. 9. The segments I 62 andv IM-are then clamped against movement and thevarious blades :54 are again clamped against movement inJi-he head 50. The cutter blades 54 by this operation 1 have thus been shifted radially with respect to the axis of rotation of the headfii) by a distance equal to half of the pitch of, or half of the distance between the high points of, the ribs of the cutter blade 56. piece of work is machinedwith the cutter-blades 54 shifted-as above described and is indicated in Fig. 9, the high points of the serrations 24 thus formed upon the piece of-work'will be '10- cated in the same relative positions radially of the axis of rotation of the'head 56 aszthe low points of the serrations formed on the'previously machined piece of work with the previous setting of the blades 54. Consequently when this second piece of work is arranged in end-to-e'nd i and abutting relationship with respect toth.

first serrated,

serrated end of thepi'ece of work; the serrations; of the two pieces will accurately and completely interfit with; one another. With such arrangement of serrations on thetwo pieces,- where the two pieces are cylindrical shafts. or shaft sections, for instance, the two shaftsmay, as will be readily appreciated, be

arranged in concentric relation with respect to each other. and with the serrations of both pieces accurately interfitting one another so that, while the serrations of the two pieces are'maintained in interfitting relationship, relative movement betweenthe abutting faces of the two pieces in the plane of abutment is positively prohibited Consequently when another cess opening thereonto, said enemas excepting "only in the direction of. length of the serrations. Gne of the principal a'dvantagesbf the construction above described ,is'the long life of the cutter blades 54. Where'the "cutting edges$d i of "such blades become worn-pr; dull they-various blades may he removed andthat face of the grooves 62 of each thereof ccoperatingwith the periphery of the cutterwblades to formthe cut.

siderably deeper than the thickness ofthe heads of these screws so as to permit thento rotate the cutterblades 54 through a distance initially much greater thanthat required to bringthe edge of the slots 62 .mentionedinte contact with the radially disposed wall of the. corresponding notch 96 in the plate !2 .and which, .as previous ly lmentioned, serves to locate the cutting edges li lradially with respect to the rotation of the head Bil. Should the re-sharpening of the blades 54 widen the slots 8'2 to such an extent that the heads of the screws 92 strike" the bot.- tom of their corresponding recesses ,94,the keys 9d shown may 'be replaced with) wider keys which will thereupon permit the blades to, be

sharpened a number of additional. times before such keys areagain required to be replaced with wider keys. Having the above in mind it willlbe appreciated that each cutter blade 54 may be Iresharpened a great many times before its area of contact with the walls 0f "'the recesses ii! is reduced to such an extent asto render it in'ad visable to attempt any further sharpening of the blades. I

vlilav il'l'glhus described my invention what. I claim by Letters Patent is? What is claime'dis; 3

1-. A "cutting tool comprising, in combinati'onga rotatable head having an axial end face and a radially disposed recess in said, face arranged with,

its center line substantially in a plan perpem di-cular to the axis of rotation of said head, a cutting element rotatably mounted in saidrecess, said cutting element having a cutting edge in substantial parallelism with the aids of rotation thereof in saic'l'headand means releasably clamp} ing said element against rotational Inovementln said recess. I

2. A cutting tool comprising; in combination,

a rotatable head having an axially'exposedface v provided with a generally radially disposed rerecess being arranged with its center line substantially in a plane perpendi'cular to the axis of said head, a cuttin element-received in said recess, said'cut-ting element comprising a generally circular member, a plurality of ribs formed integrally'w-ith and extending aboutsaid member in axially spaced re lation with respect to each other axially of said member, saidv 'member being longitudinally grooved whereby to present said ribs in crosssectional configuration to provide a cutting edge in substantial parallelism with the axis thereof, said member being positioned in 'said'rec'ess with said cutting edge thereof eXposed,.ax-ially outwardly beyond and-insubstantial parallelism with said axial 'ifia'c'e of said head, andlmeans .rel'eas-i ably clamping said member against movement infsai'd recess. l i

131A cutting tcol' coniprising, combination, a rotatable headIhavin-g an axialfend face, a

generally cylindrical "cuttmgrelementu extending,

radially. with respect to "said 'facefribs on the exterior surface of said elem'entflspaced ifrom one another axially of said element and extending in a generally circumferential direction there-l about, said element being longitudinally grooved whereby to provide a cutting iface presenting said ribs in sectional configurati'on'rto provide a .ser-

rated cutting edganieans mounting :said cutting element 'on {Said head' for Ladjusting "movement about the 'axis' of "said element; and means 7 for locking-said element in rota'tab-ly adjusted position about its "axis with said' cutting edge thereof exposed axially outwardly beyond said end face "of said head and in substantial parallel relation t'o'the plane thereof. 1

4. In ia cutting tool in combination, alrotatah supporting. head having end face. plurality fof radially disposed singularly spaced cutting elements'arranged witntheir axes parallel to andsegrnentally exposed on said face, each of said refitting elements comprising a member having externally ribbe digenerally cylindrical body portion and each being longitudinally grooved to provide acutting surface intersecting said ribs to form'a serrated cuttingedge projecting outwardly beyond and" substantially parallel to said :face, means cooperatinglwith said ele ments locating' said cutting edge of each 'ofsai'd elements in radial relation with respect to the axis of rotation of saidhead, and means releas ablysecuri ng said elements against movement in saidhe'ad. 1

' 5.:A cutting tool. comprising; in combination;

a rotatable head having an axial "end faceirlprovided with a'plurality of 'radi'ally disposed 'recesses therein in parallel relation with respect l to saidiface, a cutting element received in each of said recesses and projecting axially outwardly: beyond said end face, eachvof "said cutting elements being adjustableabout its "axis said head;

ribsi'fo'rln-ed inte'grallywith each of said elements encircling thesarne inxspaced relationto each other'axially thereof, said "elements each being longitudinally grooved whereby topresent a cut-' ting face intersecting said rib-s thereon to pro vide a serrated cutting edge, means cooperating with said cutting face of each of said elements operableto'locate said cutting edge of each of said element's radially with respect to, the axis of rotation of said head and in outwardly spaced and' parallel relation with respect to 'saidface,

and releasable means for securing said elements against'movement in said heady a 6.: A cutting tool comprising, in combination, a rotatable head; having {an axially exposed end face lprovid-edwvitha plurality of radially disposed cutting element receiving recesses therein, a cutting element received in each of these said recesses and each comprising "a generally cylindrical 'mernber arranged with its axis substantially "parallel to; said" face and having a grooved peripheral surface with the grooves thereof; spaced from each other axially of said member; each of said members having a lOngitJ/lrdinally extending groove in the peripheral surface thereof one side wall of which serves to provide a cutting face intersecting said grooved peri'pheral surface of said member top-rovide a serrated cutting edge, said members being arranged in their respective recesses to present said cutting edges thereof axially outwardly beyond and parallel to said end face of said head, and means cooperating between said head and. that wall of the groove of each of said members opposite said cutting face: thereof for holding said members against rotation in their recesses under the force of a cutting operation. I v

7. A cutting tool comprising, in'c-ombination, a rotatable head having an axially disposed face provided with generally radially disposed recesses therein in parallel relation with respect to said face, a cutting element received in each of said recesses with a segment of each projecting outwardly therefrom axially beyond said axial face of said head, each of said cutting elements comprising a member having a generally cylindrical threaded surface, each of said'members being longitudinally grooved whereby a side wall of said groove forms a cutting face intersecting said threaded portion of said member toform a serrated cutting edge in generally parallel relation to the axis thereof, said members being what ably adjustable in said recesses about'their axes and beingadjusted to position said cutting edges thereof at the position of maximum projection outwardly beyond said end face of said head, and means for releasably securing said members against movement in said recesses. s

8. A cutting tool comprising,.in combination, a rotatable head having an axially disposed end face provided with a plurality of angularly spaced generally radially disposed recessestherein, a cutter member removably received in each of said recesses and including a generally cylindrical main body portion having a generally circumferentially grooved peripheral surface, each of said cutter members being longitudinally grooved whereby one side of said groove serves to form a cutting surface intersecting the grooved peripheral surface of said member to form aserrated cutting edge, means cooperating with-said side of said groove of each of said members forming said cutting surface for locating said cutting edge of each of said members in a predetermined re-' lation with respect to said head, and-meanscooperating between the remaining side wallof the groove of each ofsaid members and said head serving to resist rotational movement of said member under the force of a cutting operation.

head having an axially exposed end face provided with a plurality of angularly spaced generally radially disposed recesses opening thereonto, a cutter member removably :received in each of said recesses, each of said cutter members comprising a generally cylindrical main body portion and reduced concentric end portions, said main body portion of each of said cutter members projecting from said recess axially outwardly beyond said end face and its periphery being grooved, each of said cutter members having a longitudinally extending groove in said main body portion thereof whereby to provide a cutting face intersecting the grooved periphery of said main body portion to provide a serrated cutting edge, said cutter members each being rotatably adjusted about its axis in its correspondin recess to bring said cutting edge thereof at a position of maximum distance outwardly of said end face of said head, and means cooperating with said reduced ends of each of said cutter members for removably securing said cutter members in said head.

9. In a cutting tool, in combination, a rotatable 10. In a cuttingtool, in combination, a rotatable head having an axially exposed end face provided with a plurality of angularly spaced generally radially disposed recesses opening thereonto, a cutter member removably'received in each of sa d recesses, each of said cutter-members comprising a generally cylindrical main body portion and M reduced concentric end portions,*said main-body portion of each of said cutter members projecting from said recess axially outwardly beyond said end face and its periphery being grooved, eachof said cutter members having a longitudinally extending groove in said main body portion thereof whereby to provide a cutting face intersecting the grooved periphery of said main body portion to provide a serrated cutting edge, said cutter members each being rotatably adjusted about its axis in its corresponding recess to bring said cutting edge thereof at a position of maximum distance axially outwardly of said end face of said head, 7 means cooperating with the reduced radially outer ends of each of'said members and'means cooperating with the reduced radially inner endsof each of said members for retaining said members in said recesses, and means fixed with respect to the last mentioned means cooperating with said cutting surface of each of said cutter members for locating said cutting edges thereof'in predetermined relation with respect to said head.

11. In a cutting tool, in combination, a rotatable head having an axially exposed end face provided with a plurality of angularly spaced generally radially disposed recesses opening thereonto, a cutter member removably received in each of said recess, each ,ofsaid cutter members comprising a generally cylindrical mainbody portion and reduced concentric end portions, said main body portion of each of said cutter members projecting from said recess axially outwardly be yond said end face and its periphery being grooved, each of said cutter members having a longitudinally extending groove in said main body portion thereof whereby to provide a cutting face intersecting the grooved periphery of said main body portion to provide a serratedlcuttingedge,

said cutter members eachbeing rotatably adjusted aboutits axis inits corresponding recess to bring said cutting edgethereof mum distance axially outwardly of said end face of said head, means cooperating with the reduced radially outer end of each of said cutter members and means cooperating with the reduced radially inner end of each of said cutter members for removably securing said cutter members in sai head, the last mentioned means comprising a member cooperating with all of said cutter members and including portions. overlying said reduced radially inner ends only thereof and other portions overlying a portion of saidmain body portion of each of said cutter members and receivable in said groove thereof.

12. A cutting tool comprising, in combination, a rotatable head having an axially disposed end face provided with a plurality of angularly spaced recesses opening thereonto, a cutting element removably received in each of saidrecesses and having a limited amount of endwise movement therein, each of said cutting elements having a grooved surface and a cutting face cooperating therewith to provide a serrated cutting edge, a pair of relatively movable locating elements mounted'on said head in adjacent relationship to each of saidc'utting'eleme'nts for movement, toward and away from the corresponding cutting at a position of maxi,

elements in a direction transverse to the length thereof, each of said cutting elements having an end serrated for complementary engagement with the grooved surface of the corresponding of said cutting members, the serrations on the ends of each pair of said locating elements being so constructed and arranged that each requires a different axial position of the associated cutting element to permit its serrated end to be complementarily engaged therewith, the serrated ends of corresponding of said elements being simultaneously engaged with said cutting elements thereby to locate all of said cutting elements with the grooves thereof at corresponding distances from the axis of rotation of said head, and means for releasably locking said locating elements in slidably adjusted position.

13. A'cutting tool comprising, in combination, a rotatable head having an axially exposed end face provided with a plurality of generally radid ally disposed angularly spaced recesses therein, a generally cylindrical cutting element removably received in each said recesses and having a grooved peripheral surface, each of said cuttin elements being longitudinally grooved whereby to provide a radially disposed cutting face intersecting said grooved perpiheral surface to provide a serrated cutting edge, said head having a circular groove in said end face thereof in concentric relation with respect to the axis of rotation thereof, a pair of segments received in said groove between each adjacent pair of said cutting elements, said segments being slidable relative to each other in said groove, means for releasably locking said segments in slidably adjusted position in said groove, said groove intersecting said recesses and one end of each of said segments being serrated for complementary engagement with said grooved exterior surface of the cooperating of. said cutting elements, the serrations on the end of one segment of each of said pairs of segments being out of phase with the serrations RENE: H. TOUBHANS. 

